Emulsion polymers and low voc coating compositions made therefrom

ABSTRACT

Emulsion polymers and coating compositions made therefrom that exhibit exceptional roller stability and stain resistance to both hydrophilic and hydrophobic stains, without sacrificing scrub resistance. The emulsion polymers include, as polymerized units formed at a pH between 3 and 9: a) at least one nonionic or anionic unsaturated monomer in an amount ranging between about 78 wt. % to less than 100 wt. % based on the overall weight of the polymer composition b) one or more strong acid monomer in an amount ranging from about 0.01 wt. % to 2 wt. % based on the overall weight of the polymer composition; and c) at least one lower alkyl acrylate monomer in an amount ranging between about 1 wt. % to 20 wt. % based on the overall weight of the polymer composition.

This application is related to and claims the benefit of U.S.Provisional Application No. 62/261,958, entitled EMULSION POLYMERS ANDLOW VOC COATING COMPOSITIONS MADE THEREFROM filed on Dec. 2, 2015, thecontents of which are incorporated herein by reference.

FIELD OF THE INVENTION

This disclosure relates generally to emulsion polymers used in coatings,adhesives, sealants, and the like. More specifically, this disclosurerelates to coating compositions that include emulsion polymers thatenhance stability of the coating composition and provide the resultingfilm or coating layer with resistance to hydrophilic and hydrophobicstains.

BACKGROUND OF THE INVENTION

The statements in this section merely provide background informationrelated to the present invention and may not constitute prior art.

Driven by lower VOC requirements, softer polymers with low minimum filmformation temperature (MFFT) are increasingly being utilized inwaterborne architectural coatings. However, coating compositions basedon these polymers result in soft and tacky coating layers or films thatexhibit high soiling tendency and poor wash and burnish resistance.Washability, which defines a coating's ability to withstand a scrubbingaction designed to remove a stain without changing the appearance orprotective functions of the coating, is a desirable property that islacking in most commercial latex paints. This property is particularlyhard to attain in “flat” interior wall paints.

Adding to this challenge is the wide variation in chemical and physicalcharacteristics exhibited by household stains that are encountered. Acoating formulation is often optimized for hydrophobic stain washabilityat the expense of hydrophilic stain removal or vice versa. Since onemechanism of stain removal involves the mechanical erosion of the paintlayer or film, a latex paint that exhibits good stain removal oftenexhibits poor scrub resistance.

Polymers that contain strong acid groups are used in a variety ofcoatings, inks, and adhesives. The strong acid groups provide forimproved adhesion of the polymer to substrates, form crosslinks in thepresence of divalent metal ions, and promote adsorption of the polymeronto pigment particles, such as titanium dioxide. U.S. Pat. Nos.8,158,713 and 8,318,848 provide waterborne coating compositions thatinclude a vinyl copolymer having phosphorous-containing functionalgroups. U.S. Pat. No. 6,485,786 discloses an aqueous stain-blockingcoating composition that includes an aqueous emulsion copolymer havingpolymerized units derived from an ethylenically unsaturated nonionicmonomer and an ethylenically unsaturated strong acid monomer. U.S. Pat.No. 6,710,161 describes a polymer composition that includes co-polymerparticles bearing phosphorus acid groups dispersed in an aqueous medium.EP Patent No. 1,988,105 discloses an aqueous copolymer dispersionobtained from a mixture of an ethylenically unsaturated nonionicmonomer, a phosphorous-containing monomer, an alkoxysilane functionalmonomer, and a sulfur-based monomer. U.S. Pat. Nos. 3,736,287 and3,749,690 describe an aqueous polymer emulsion derived from theinterpolymerization of a short-chain alpha, beta-unsaturated mono- orpolycarboxylic acid, acrylonitrile, a short-chain alpha,beta-unsaturated amide, an alkyl acrylate, and vinyl acetate or an alkylmethacrylate.

SUMMARY OF THE INVENTION

The present invention generally provides an emulsion polymer comprising,as polymerized units: a) at least one nonionic or anionic unsaturatedmonomer in an amount ranging between about 78 to less than 100 wt. %,preferably about 79 to 99.5 wt. %, based on the overall weight of thepolymer composition; b) one or more strong acid monomer in an amountranging from about 0.01 to 2 wt. %, preferably 0.01 to 1.5 wt. %, basedon the overall weight of the polymer composition; and c) at least onelower alkyl acrylate monomer in an amount ranging between about 1 to 20wt. % based on the overall weight of the polymer composition. Thepolymerized units are formed at a pH between 3 and 9, preferably between3 and 8.

According to one aspect of the present disclosure, the ethylenicallyunsaturated monomer may be without limitation any (meth)acrylates,unsubstituted and substituted vinyl esters, unsubstituted andsubstituted styrene, carboxylic or dicarboxylic acids or amides, or amixture thereof, while the strong acid monomer may be without limitation(meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonicacid, cinnamic acid, ethyl methacrylate phosphate, phosphate esters ofpolyethylene glycol mono(meth)acrylate, phosphate esters ofpolypropylene glycol mono(meth)acrylate, or a mixture thereof, and thelower alkyl acrylate monomer is methyl acrylate, ethyl acrylate, propylacrylate, or a mixture thereof.

According to another aspect of the present disclosure, a coatingcomposition is provided that comprises the emulsion polymer dispersed inan aqueous medium. The emulsion polymer may be present in an amountranging from about 5 to 70 wt. %, alternatively, 10 to 60 wt. %, orpreferably 20 to 60 wt %, based on the entire weight of the coatingcomposition. The coating composition may further comprise an organicpigment, and inorganic pigment, or a mixture thereof. When desirable,the coating composition may also comprise one or more additives,including but not limited to, surfactants, dispersants, extenders,rheology modifiers, defoamers, coalescent agents, and opacifiers. Thecoating composition comprises less than about 50 grams per liter of avolatile organic compound (VOC).

According to yet another aspect of the present disclosure, a method ofusing the coating composition includes applying the composition to asurface of a substrate to form a film or coating layer on the surface,such that the film or coating layer is resistant to hydrophilic stainsand hydrophobic stains. The total ΔE measured for the resistance of thecoating composition to the hydrophilic stains and hydrophobic stains isless than about 80. The total ΔE measured for the resistance of thecoating composition to hydrophilic stains is less than about 40. Thetotal ΔE measured for the resistance of the coating composition tohydrophobic stains is less than about 35. In some embodiments, the totalΔE measured for the resistance of the coating composition to theconsumer union stain is less than about 1.5. The hydrophilic stainsinclude mustard, ketchup, wine, coffee, and fountain ink, while thehydrophobic stains include ballpoint pen, No. 2 pencil, blue crayon,grease pencil, 2 red lipsticks (lipstick #1, and lipstick #2) and aconsumer union black stain.

According to yet another aspect of the present disclosure, rollerstability of the coating is four (4) cycles.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is in no wayintended to limit the present disclosure or its application or uses. Forexample, the emulsion polymers made and used in coating compositionsaccording to the teachings contained herein is described throughout thepresent disclosure in conjunction with an architectural paint in orderto more fully illustrate the composition and the use thereof. Theincorporation and use of such emulsion polymers as coating compositionsused in other applications or as an adhesive, a caulk, a sealant, amastic, or the like are contemplated to be within the scope of thepresent disclosure. It should be understood that throughout thedescription, corresponding reference numerals or letters indicate likeor corresponding parts and features.

In the context of the present disclosure, washability or stain removalrefers to a coating's ability to withstand a scrubbing action thatremoves the staining material(s) without changing the coating'sappearance or protective function. The term “nonionic monomer” as usedherein is meant to indicate that the monomer does not bear an ioniccharge within the pH range of 2 to 10. The term “anionic monomer” asused herein means being ethylenically unsaturated mono- or di-carboxylicacid monomer

The present disclosure generally provides emulsion polymers and coatingcompositions made therefrom, as well as uses thereof. The emulsionpolymers comprise, consist of, or consist essentially of an emulsionpolymer having, as polymerized units: (a) at least one ethylenicallyunsaturated monomers in an amount ranging from about 78 wt. % to lessthan 100 wt. %; (b) one or more strong acid monomers in an amountranging from about 0.01 to 2 wt. %; and (c) at least one lower alkylacrylate monomer in an amount ranging between about 1 to 20 wt. % basedon the overall weight of the polymer composition. According to oneaspect of the present disclosure, the polymerized units are formed at apH between 3 and 9.

The ethylenically unsaturated monomer (a) is not limited to any specificethylenically unsaturated monomer. The ethylenically unsaturatedmonomers may include, without limitation, mono- or di-carboxylic acidmonomer such as (meth)acrylic acid, maleic acid, fumaric acid, itaconicacid, crotonic acid, citraconic acid, cinnamic acid; (meth)acrylic estermonomers such as butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate,lauryl acrylate, methyl methacrylate, butyl methacrylate, isodecylmethacrylate, lauryl methacrylate, hydroxyethyl methacrylate,hydroxypropyl methacrylate; (meth)acrylonitrile; (meth)acrylamide;diacetone acrylamide, methylol (meth)acrylamide, glycidyl methacrylate,4-hydroxybutyl acrylate glycidyl ether; amino-functional andureido-functional monomers (e.g., Norsocryl® 104, Arkema Inc., King ofPrussia, Pa.); monomers bearing acetoacetoxy-functional,acetoacetamido-functional, and/or cyanoacetamido-functional groups;styrene and substituted styrenes; butadiene; ethylene, propylene,alpha-olefins such as 1-decene; vinyl acetate, vinyl propionate, vinylbutyrate, vinyl versatate esters (e.g., VeoVa™ 10 and VeoVa™ 12 fromMomentive Performance Materials, CT) and other vinyl esters; and vinylmonomers such as vinyl chloride, vinylidene chloride. Alternatively, theethylenically unsaturated monomer is butyl acrylate, methylmethacrylate, butyl methacrylate, 2-ethylhexyl acrylate, styrene,another acrylic monomer, methacrylic acid, acrylic acid, itaconic acid,or a mixture thereof. Methacrylic acid, butyl acrylate, methylmethacrylate, butyl methacrylate, styrene are preferred.

The amount of the ethylenically unsaturated nonionic monomer (a) isbetween about 78 wt. % and less than 100 wt. %, preferably between 79and 99 wt. %, based on the entire weight of the emulsion polymer,wherein the term “about” refers to ±0.1, alternatively, ±0.05.Alternatively, the amount of the ethylenically, unsaturated nonionicmonomer is greater than about 83 wt. %; alternatively, between about 89to 99 wt. %.

The strong acid monomer (b) is selected as one from the group of aphosphorus-based acid monomer, a sulfur-based acid monomer, or a mixturethereof. The amount of the strong acid monomer in the emulsion polymeris within the range of about 0.1 wt. % to 2 wt. % based on the weight ofthe entire emulsion polymer. Alternatively, the amount of the strongacid monomer is between about 0.2 wt. % and 1.5 wt. %. When desirable,the amount of the first acid monomer is between about 0.25 wt. % and 1wt. %, wherein the term “about” refers to ±0.1, alternatively, ±0.05.

The strong acid monomer (b) is not limited to any specific type ofphosphate or sulfate or sulfonate monomer. Phosphate-based monomersinclude, but are not limited to, phosphoalkyl (meth)acrylates oracrylates, phospho alkyl (meth)acrylamides or acrylamides, phosphoalkylcrotonates, phosphoalkyl maleates, phosphoalkyl fumarates,phosphodialkyl (meth)acrylates, phosphodialkyl crotonates, vinylphosphates and (meth)allyl phosphate, phosphate esters of polypropyleneglycol mono(meth)acrylate or polyethylene glycol mono(meth)acrylate,polyoxyethylene allyl ether phosphate, vinyl phosphonic acid.Sulfate-based and sulfonate-based monomers include, without limitation,vinyl- and allyl-sulfonic or sulfuric acids, sulfoethyl (meth)acrylate,aryl-sulfonic or sulfuric acids, (meth)acrylamidoethane-sulfonic orsulfuric acids, methacrylamido-2-methyl propane-sulfonic or sulfuricacids, and the alkali metal salts of sulfonic and sulfuric acids, sodiumstyrene sulfonate, or vinyl sulfonic acid. Alternatively, the strongacid monomer is an alkyl methacrylate phosphate, such as ethylmethacrylate phosphate (PAM1); phosphate esters of polypropylene glycolmonomethacrylate (PAM2); or mixtures thereof. Specific examples of PAM1and PAM2 include, but are not limited to Sipomer® PAM 4000, Sipomer® PAM300, Sipomer® PAM 200 and Sipomer® PAM 100 (Solvay), respectively. TheSipomer® PAM series are preferred.

The lower alkyl acrylate monomer (c) is not limited to any specificalkyl acrylate monomer, but rather the term “lower alkyl” is defined asbeing an alkyl group with 1-3 carbon atoms. The alkyl acrylate monomersmay include, without limitation, methyl acrylate, ethyl acrylate, orpropyl acrylate. Alternatively, the alkyl acrylate monomer is methylacrylate, ethyl acrylate, or a mixture thereof. Methyl acrylate andethyl acrylate are preferred.

The amount of the lower alkyl acrylate monomer (c) in the emulsionpolymer is within the range of 1 to 20 wt. % based on the weight of theentire emulsion polymer. Alternatively, the amount of the lower alkylacrylate monomer is between about 3 to 15 wt. %. When desirable, theamount of the alkyl acrylate monomer is between about 5 to 10 wt. %,wherein the term “about” refers to ±0.5, alternatively, ±0.1.

A non-exhaustive list of possible monomer combinations that may bepolymerized or used to form the emulsion polymers according to theteachings of the present disclosure is provided in Table 1. The monomersassociated with the abbreviations used in Table 1 include: butylacrylate (BA); methyl methacrylate (MMA); another acrylic monomer (AM);ethylmethacrylate phosphate (PAM1); phosphate esters of polypropyleneglycol monomethacrylate (PAM2); and methacrylic acid (MAA).

TABLE 1 Several Specific Combinations of Monomers Used to Form EmulsionPolymers (c) Lower Alkyl (a) Ethylenically (b) Strong Acid AcrylateUnsaturated Monomer Monomer Monomer BA, MMA, AM, MAA PAM1 MA BA, MMA,AM, MAA PAM2 MA BA, MMA, AM, MAA PAM1, PAM2 MA BA, MMA, AM, MAA PAM1 EABA, MMA, AM, MAA PAM2 EA BA, MMA, AM, MAA PAM1, PAM2 EA BA, MMA, AM, MAAPAM1 MA, EA BA, MMA, AM, MAA PAM2 MA, EA BA, MMA, AM, MAA PAM1, PAM2 MA,EA

According to one aspect of the present disclosure, coating compositionscomprising the emulsion polymers dispersed in an aqueous medium areformed. The emulsion polymers are incorporated into the coatingcompositions in an amount ranging from about 5 wt. % to 70 wt. % basedon the total weight of the coating composition; alternatively, betweenabout 10 wt. % and 60 wt. %. Alternatively, the amount of the emulsionpolymers present in the coating composition is greater than about 10 wt.%; alternatively, less than about 55 wt. %, based on the total weight ofthe coating composition.

The coating compositions may further comprise a dye, a pigment, or amixture thereof. These pigments may act as colorants, fillers, orextenders with several specific examples including, but not beinglimited to, carbon black, colored organic pigments, and metal oxidepigments, such as titanium dioxide, zinc oxide, clay, aluminum silicate,zinc oxide, zinc hydroxide, aluminum silicate, magnesium silicate,calcium silicate, amorphous silica, vapor phase silica, colloidalsilica, alumina, aluminum hydroxide, zirconium oxide, and cerium oxide,as well as calcium carbonate, magnesium carbonate, kaolin, clay, talc,calcium sulfate, barium sulfate, and zinc carbonate.

When desirable, the coating compositions may also comprise one or moreadditives, including, but not limited to, surfactants, dispersants,rheology modifiers, defoamers, coalescent agents, or opacifiers. Varioussurfactants and defoamers may include any organic, organosilicon, andsilicone molecules that are well known to one skilled-in-the-art tofunction in such a capacity. In order to enhance the weatherability ofthe film or coating formed from the coating composition, the coatingcomposition may include hindered amines or UV absorber molecules.Several specific examples of surfactants or dispersants include withoutlimitation ionic and nonionic compounds, such as alkyl polyglycolethers, alkyl phenol polyglycol ethers, alkali metal or ammonium saltsof alkyl, aryl or alkylaryl sulfonates, sulfates, phosphates, and thelike.

The coating compositions may be applied to the surface of a substrate byany conventional application method known to one skilled in the art,including but not limited to brushing, draw-down methodology, spincoating, dip coating, flow coating, curtain coating, roller application,and spray methodology, for example, air spray, air-assisted spray,airless spray, high volume low pressure (HVLP) spray, and air-assistedairless spray. Films or coating layers formed using these coatingcompositions exhibit excellent resistance to a wide range of hydrophilicand hydrophobic stains. Conventional coating formulations are oftenoptimized for hydrophobic stain washability at the expense ofhydrophilic stain removal and vice versa. One benefit associated withthe emulsion polymers of the present disclosure and the coatingcompositions formed thereform is the capability of providing for theefficient or clean removal of both hydrophilic and hydrophobic stains,while maintaining good scrub resistance. The coating compositions formedaccording to the teachings of the present disclosure also exhibitenhanced roller stability.

According to another aspect of the present disclosure, in one embodimentan emulsion polymer comprising, as polymerized units:

-   -   a) at least one nonionic or anionic unsaturated monomer in an        amount ranging between about 78 wt. % to less than 100 wt. %        based on the overall weight of the polymer composition;    -   b) one or more strong acid monomer in an amount ranging from        about 0.01 wt. % to 2 wt. % based on the overall weight of the        polymer composition; and    -   c) at least one lower alkyl acrylate monomer in an amount        ranging from about 1 wt. % to 20 wt. % based on the overall        weight of the polymer composition.        The polymerized units of the emulsion polymer are formed at a pH        between 3 and 9. In this embodiment, the ethylenically        unsaturated monomer is without limitation methacrylic acid,        butyl acrylate, methyl methacrylate, butyl methacrylate,        styrene, or a mixture thereof. The strong acid monomer may        include, but not be limited to ethyl methacrylate phosphate,        phosphate esters of polyethylene glycol mono(meth)acrylate,        phosphate esters of polypropylene glycol mono(meth)acrylate, or        a mixture thereof and the lower acrylate monomer is without        limitation methyl acrylate, ethyl acrylate, propyl acrylate, or        a mixture thereof.

According to a second embodiment, a coating composition is provided thatcomprises the emulsion polymer described in the first embodiment abovedispersed in an aqueous medium. The coating composition may furthercomprise an organic pigment, and inorganic pigment, or a mixturethereof. When desirable, the coating composition may also comprise oneor more additives selected from the group of surfactants, dispersants,extenders, rheology modifiers, defoamers, coalescent agents, andopacifiers. The emulsion polymer is present in the coating compositionin amount that ranges from about 5 to 70 wt. % based on the entireweight of the coating composition; alternatively, between about 10 to 55wt. % based on the entire weight of the coating composition. The coatingcomposition comprises less than about 50 grams per liter of a volatileorganic compound (VOC).

According to a third embodiment, a method of using the coatingcomposition defined in the second embodiment above is provided, whereinthe coating composition is applied to a surface of a substrate to form afilm or coating layer on the surface that is resistant to bothhydrophilic stains and hydrophobic stains. The hydrophilic stainsinclude mustard, ketchup, wine, coffee, and fountain ink; while thehydrophobic stains include ballpoint pen, No. 2 pencil, blue crayon,grease pencil, lipstick #1 (CoverGirl Hot Passion), lipstick #2(Maybelline Royal Red), and consumer union black stain. The total ΔEmeasured for the resistance of the coating composition to thehydrophilic and the hydrophobic stains is less than about 80. The totalΔE measured for the resistance of the film or coating layer tohydrophilic stains is less than about 40. The total ΔE measured for theresistance of the film or coating layer to hydrophobic stains is alsoless than about 40. The roller stability of the coating layer or film isat least four cycles.

-   1. An emulsion polymer composition comprising, as polymerized units:    -   a) at least one nonionic or anionic unsaturated monomer in an        amount ranging between about 78 wt. % to less than 100 wt. %        based on the overall weight of the polymer composition    -   b) one or more strong acid monomer in an amount ranging from        about 0.01 wt. % to 2 wt. % based on the overall weight of the        polymer composition; and    -   c) at least one lower alkyl acrylate monomer in an amount        ranging between about 1 wt. % to 20 wt. % based on the overall        weight of the polymer composition.-   2. The emulsion polymer according to Claim 1, wherein the    polymerized units are formed at a pH between 3 and 9.-   3. The emulsion polymer according to any of Claims 1 or 2, wherein    the ethylenically unsaturated nonionic or anionic monomer is    methacrylic acid, butyl acrylate, methyl methacrylate, butyl    methacrylate, styrene;    -   wherein the strong acid monomer is ethyl methacrylate phosphate,        phosphate esters of polypropylene glycol monomethacrylate, or a        mixture thereof; and    -   wherein the lower alkyl acrylate monomer is methyl acrylate,        ethyl acrylate, propyl acrylate, or a mixture thereof.-   4. A coating composition comprising an emulsion polymer dispersed in    an aqueous medium, the emulsion polymer comprising, as polymerized    units:    -   a) at least one nonionic or anionic unsaturated monomer in an        amount ranging between about 78 wt. % to less than 100 wt. %        based on the overall weight of the polymer composition    -   b) one or more strong acid monomer in an amount ranging from        about 0.01 wt. % to 2 wt. % based on the overall weight of the        polymer composition; and    -   c) at least one lower alkyl acrylate monomer in an amount        ranging between about 1 wt. % to 20 wt. % based on the overall        weight of the polymer composition;    -   wherein the polymerized units are formed at a pH between 3 and        9.-   5. The coating composition according to Claim 4, wherein the coating    composition comprises less than about 50 grams per liter of a    volatile organic compound (VOC).-   6. The coating composition according to any of Claims 4 or 5,    wherein the ethylenically unsaturated nonionic or anionic monomer is    methacrylic acid, butyl acrylate, methyl methacrylate, butyl    methacrylate, styrene;    -   wherein the strong acid monomer is ethylmethacrylate phosphate,        phosphate esters of polypropylene glycol monomethacrylate, or a        mixture thereof; and    -   wherein the lower alkyl acrylate monomer is methyl acrylate,        ethyl acrylate, propyl acrylate, or a mixture thereof.-   7. The coating composition according to any of Claims 4-6, wherein    the coating composition further comprises an organic pigment, and    inorganic pigment, or a mixture thereof.-   8. The coating composition according to any of Claims 4-7, wherein    the coating composition further comprises one or more additives    selected from the group of surfactants, dispersants, extenders,    rheology modifiers, defoamers, coalescent agents, and opacifiers.-   9. The coating composition according to any of Claims 4-8, wherein    the emulsion polymer is present in an amount ranging from about 5 to    70 wt. % based on the entire weight of the coating composition.-   10. The coating composition according to Claim 9, wherein the    emulsion polymer is present in an amount ranging from about 10 to 50    wt. % based on the entire weight of the coating composition.-   11. A method of using the coating composition according to any of    Claims 4-10, wherein the coating composition is applied to a surface    of a substrate to form a film or coating layer on the surface;    -   wherein the film or coating layer is resistant to both        hydrophilic stains and hydrophobic stains,    -   wherein the hydrophilic stains include mustard, ketchup, wine,        coffee, and fountain ink;    -   wherein the hydrophobic stains include ballpoint pen, No. 2        pencil, blue crayon, grease pencil, lipstick #1 (CoverGirl Hot        Passion), lipstick #2 (Maybelline Royal Red), and consumer union        black stain.-   12. The method according to Claim 11, wherein the total ΔE measured    for the resistance of the film or coating layer to the hydrophilic    and the hydrophobic stains is less than about 80.    -   The method according to Claim 12, wherein the total ΔE measured        for the resistance of the film or coating layer to hydrophilic        stains is less than about 40;        -   The method according to Claim 12, wherein the total ΔE            measured for the resistance of the film or coating layer to            hydrophobic stains is less than about 35.-   13. The method according to any of Claim 11-14, wherein the roller    stability of the coating layer or film is at least four cycles.

The following specific examples are given to further illustrate thepreparation and testing of emulsion polymers and coating formulationscontaining the emulsion polymers according to the teachings of thepresent disclosure and should not be construed to limit the scope of thedisclosure. Those skilled-in-the-art, in light of the presentdisclosure, will appreciate that many changes can be made in thespecific embodiments which are disclosed herein and still obtain alikeor similar result without departing from or exceeding the spirit orscope of the disclosure.

Example 1: Emulsion Polymer Composition and Method for Preparing Thereof

Comparative Sample 1 is prepared by adding a total of 17.9 gram of aseed latex and 495 gram water into a three-liter, jacketed glass reactorequipped with dual impellers, reflux condensers, and stainless steelfeed lines. The reactor is then heated to 65° C. A monomer mixturecontaining 594.5 gram butyl acrylate (BA), 526.2 gram methylmethacrylate (MMA), 23.6 gram acrylic monomer (Norsocryl® 104, ArkemaInc., King of Prussia, Pa.), and 8.7 gram methacrylic acid (MAA) arecombined with water and then emulsified using equal active amounts ofsodium dodecylbenzene sulfonate and alkyldiphenyloxide disulfonate underagitation.

The polymerization is initiated at 65° C. using t-butyl hydroperoxide(t-BHP) solution as an oxidizer and sodium metabisulfite (SMBS) as areducer. Commencing simultaneously, monomer pre-emulsion, ammoniumhydroxide solution, oxidizer and reducer solutions are fed to thereactor over a period of 210 minutes and 220 minutes, respectively. Thetemperature is maintained at 80° C. after initiation. At the end ofoxidizer and reducer feeds, the reactor is held at 75° C. for 30minutes. Then, additional t-BHP and SMBS solutions are fed over 60minutes to lower the amount of residual monomers. The pH of theresulting latex is adjusted to 8.0-9.0 with 28% ammonium hydroxide. Thesolid content of the latex is ˜50%. The emulsion polymer may then becollected or stored as an aqueous dispersion or latex.

Comparative Sample 2 is prepared using the same procedure as describedin Comparative Sample 1, except that the monomer mixture contained 567.8gram BA, 495.2 gram MMA and 57.7 gram Methyl Acrylate (MA) while keepingthe MAA and Norsocryl® 104 amounts the same to maintain a similarcalculated polymer glass transition temperature (Tg) using the Foxequation as the guide.

Comparative Sample 3 is prepared using the same procedure as describedin Comparative Sample 1, except that the monomer mixture contained 553.3gram BA, 509.7 gram MMA and 57.7 gram Ethyl Acrylate (EA) while keepingthe MAA and Norsocryl® 104 amounts the same.

Comparative Sample 4 is prepared using the same procedure as describedin Comparative Sample 1, except that the monomer mixture contained 511.5gram BA, 493.9 gram MMA and 115.3 gram Ethyl Acrylate (EA) while keepingMAA and Norsocryl® 104 amounts the same.

Comparative Sample 5 is prepared using the same procedure as describedin Comparative Sample 1, except that the monomer mixture contained 596.6gram BA, 512.6 gram MMA, 23.6 gram Norsocryl® 104, 8.7 gram MAA, and 5.7gram ethyl methacrylate phosphate (PAM1).

Test Samples 6 and 7 are prepared using the same procedure asComparative Sample 5, except that the MMA amount is reduced to 455.4gram to compensate for the inclusion of 57.2 gram Methyl Acrylate (MA)and 57.2 gram Ethyl Acrylate (EA), respectively.

Test Sample 8 is prepared using the same procedure as Test Samples 6 &7, except that an equal amount of phosphate esters of polypropyleneglycol monomethacrylate (PAM2) replaced ethylmethacrylate phosphate(PAM1).

Test Sample 9 is prepared using the same procedure as Test Sample 8,except that the MMA amount is further reduced to 398.2 gram tocompensate for the inclusion of 114.2 gram Ethyl Acrylate (EA).

The amount of PAM1, PAM2, MA, and/or EA utilized in the comparativesamples 1-5 and the test samples 6-9 are summarized in Table 2 as aweight percentage based on the weight of the total monomer mixture,which also contains butyl acrylate (BA), methyl methacrylate (MMA),acrylic monomer (Norsocryl® 104, Arkema Inc., King of Prussia, Pa.), andmethacrylic acid (MMA). The total solids content associated with theemulsion polymers is also provided in Table 2 along with the volumeaverage (M_(v)) and number average (M_(n)) particle size for thecollected polymer samples measured on Nanotrac UPA150 (Microtrac).

TABLE 2 Composition & Properties of Comparative and Test EmulsionPolymer Samples Comparative Samples Test Samples BOTM* 1 2 3 4 5 6 7 8 9PAM1, (%) 0 0 0 0 0.5 0.5 0.5 0 0.5 PAM2, (%) 0 0 0 0 0 0 0 0.5 0 MA,(%) 0 5 0 0 0 5 0 5 0 EA, (%) 0 0 5 10 0 0 5 0 10 Total Solids, (%) 50.251.1 50.9 50.4 50.4 49.7 49.8 50.3 50 Mv (micron) 0.135 0.132 0.1380.134 0.137 0.137 0.137 0.136 0.137 Mn (micron) 0.111 0.107 0.115 0.1190.117 0.115 0.119 0.119 0.115 *BOTM = Based on Total Monomers, MA =methyl acrylate, EA = ethyl acrylate, PAM1 = Sipomer ® PAM 4000, andPAM2 = Sipomer ® PAM 200

Example 2: Paint Samples Formed Using the Emulsion Polymer Compositions

The comparative emulsion polymer samples 1-5 and test emulsion polymersamples 6-9 prepared in Example 1 are used in the preparation of paintsamples A-I. Each paint sample, which is comprised of the compositiondescribed in Table 3, is prepared using the same procedure, with theonly exception being the composition of the emulsion polymer sampleincorporated therein. Each paint sample is prepared by mixing thetitanium dioxide slurry with coalescent, dispersant and water using adispersator at low speed, followed by additions of ammonia, defoamer,and extender pigments. The mixture of above ingredients was then mixedat a higher speed till an acceptable Hegman fineness reading wasachieved. The dispersator speed was then reduced and final additions ofopaque polymer and thickeners were made to produce the paint base. Thepaint base was weighed out into pint-sized cans, to which appropriateamounts of latex, coalescent, and water were added. Paints were stirredon a bench top lab mixer for 5 minutes before initial KU viscosity andpH were measured. The paint samples A-I are collected and stored fortesting.

TABLE 3 Composition for Paint Samples A-I. Amount Materials (grams)Grind Water 75.8 Rutile TiO2 Slurry 287.6 Nonionic Surfactant 3 AmmoniaAQ 28% 0.5 Pigment Dispersant 16.7 Sodium-Potassium Alumina SilicateExtender 172.3 Calcined Kaolin Extender 98.5 Attagel ® Rheology Modifier3 Defoamer 1 Let Emulsion Polymer Sample (1, 2, 3, 4, 5, or 6) 324 DownAquaflow ® NHS310 Rheology Modifier 20.7 Polyurethane Rheology Modifier5.4 Coalescent 6.6 Opacifier 41.2 Water 118.7

Example 4: Testing the Stain Resistance, Roller Stability, & ScrubResistance of Paint Samples

The Paint Samples A-I as prepared in Example 2 are evaluated forresistance to staining, roller stability, and scrub resistance. RollerStability is assessed by filling half-pint paint cans with a coatingcomposition so that the can is ⅔ full. The paint can is then sealed andplaced on a mechanical roller at 25 rpm for a period of 16 to 24 hours.The paint cans are subsequently removed from the roller, and theviscosity in Krebs units (KU) of the coating composition is re-measuredand compared to the original KU value measured prior to being subjectedto the roller stability test. The process is repeated until the measuredviscosity exceeds 140 KU, the coating composition solidifies, or thecoating composition has been subjected to a total of four cycles.

Scrub resistance is measured according to a standard ASTM D-2486-79method (ASTM International, West Conshohocken, Pa.) using a 7-day drycycle. The relative scrub resistance is evaluated on a Garner StraightLine Washability and Wear Abrasion Machine. The coatings are appliedwith a wet film thickness of 7 mils (0.18 mm) over Leneta black plasticcharts and allowed to dry for 7 days at controlled temperature (CT) andcontrolled relative humidity (CH) of 77° F. and 50%, respectively. Thenylon bristle brushes used in the test are conditioned by running 400cycles before the test begins. A standardized abrasive scrub media(#SC-2 from the Leneta Company) is used in the test. A total of 7 mL ofthe scrub media and 5 mL of water are added at the beginning of the testand after every 400 cycles. The test is done in triplicate and thenumber of cycles to failure is recorded. An emulsion polymer derivedfrom a composition described in U.S. Pat. No. 8,389,061 and alsoprepared according to the method taught in U.S. Pat. No. 8,389,061 isemployed as a scrub control for each test panel evaluated.

Stain resistance is measured by determining the degree to which a staincan be removed from a film or coating layer according to a modified ASTMD-4828 method. More specifically, a 7-mil wet paint film is cast onto ablack Leneta scrub chart and dried for a minimum of three days in acontrolled temperature & humidity (CT/CH) chamber. Five hydrophilicstains (mustard, ketchup, hot coffee, red wine, and blue fountain ink)and seven hydrophobic stains (ball point pen, #2 pencil, blue crayon,grease pencil, and two red lipsticks as well as the Consumers Unionblack stain), are included in the test. Mustard, ketchup, and ConsumerUnion (CU) black stains are applied using a 10 mil square draw-down bar.For coffee, red wine, and fountain ink, a strip of a single ply papertowel is used to hold the liquid stains in place. Other hydrophobicstains are directly marked onto the scrub panels. A coating or filmformed from a commercial paint may be used as a control.

All stains are allowed to sit on the paint film for two hours while theConsumers Union (CU) stain is held in place for 24 hours. The films arewashed for 100 cycles using ASTM standard sponges and Lenetastandardized Non-Abrasive Scrub Media as the cleaning solution.Fantastik® (S.C. Johnson Company) is the cleanser for the CU stain,which is washed for 25 cycles on a Gardner Wear Abrasion machine. Thedegree of staining is assessed using the ΔE values of unstained versusstained and then washed portions of the paint film, measured by a BYKGardner spectrophotometer. The measurement is taken in triplicate andthen averaged. Small ΔE values are desirable, denoting slight or noresidual staining of the paint surface. The measurement of the ΔEassociated with each type of stain formed on and removed from thedifferent paint samples is provided in Table 4.

Referring to Table 4, the Krebs viscosity measured for the test samplesF-I is about the same as the Krebs viscosity measured for thecomparative samples A-E. In general, the individual ΔE values measuredfor the removal of the same stains on comparative samples A-E areobserved to be higher than the corresponding values measured for testsamples F-I.

TABLE 4 The Measurement of Paint Properties and ΔE for Various StainsRemoved From Paint Samples A-I Paint Sample A B C D E F G H I EmulsionPolymer 1 2 3 4 5 6 7 8 9 KU 111 104 109 106 106 103 105 103 102 ICI,(P) 1 0.9 1 1 0.9 0.9 0.9 0.9 0.9 60° Gloss 3 2.8 2.9 2.9 3 3 3 2.8 2.985° Gloss 2.8 2.6 2.7 2.6 2.7 2.2 2.4 2.6 2.3 Hydrophilic Stain RemovalMustard 11.94 12.09 11.11 10.39 11.71 3.16 8.51 7.6 11.14 Ketchup 0.840.85 1.31 0.78 1.7 1.1 1.11 1.19 0.8 Wine 7.78 7.45 7.52 7.4 6.91 5.254.67 5.02 5.05 Coffee 9.03 6.82 8.27 7.88 9.01 7.59 8.37 7.8 7.62Fountain Ink 16.95 21.04 15.87 17.42 11.32 8.35 10.46 8.67 10Hydrophobic Stain Removal Ballpoint pen 8.14 7.87 5.93 6.17 4.79 6.984.61 4.37 5.26 No. 2 pencil 2.12 3.12 2.06 3.15 2.45 2.16 2.21 1.95 2.57Blue Crayon 10.04 10.09 9.91 8.51 11.63 4.21 6.4 4.95 4.91 Grease Pencil15.46 13.37 14.69 12.92 15.05 12.52 16.8 12.54 14.9 Lipstick #1 3.252.56 2.53 2.34 3.21 2.78 2.2 1.91 3.33 Lipstick #2 1.56 1.65 2.55 1.411.51 1.47 1.63 1.89 1.63 Consumer Union (CU) Stain 2.75 2.01 2.43 1.932.12 1.34 1.41 1.3 1.15

A summary of the total value of the measured ΔE for test paint samplesF-I is provided in Table 5 along with a summary of the roll stabilityand scrub resistance. The total ΔE measured for the resistance of thecoating composition to the hydrophilic stains and hydrophobic stains isless than about 80 for test paint samples F-I; alternatively, less thanabout 75. The total ΔE measured for the resistance of the coatingcomposition (test samples F-I) to the hydrophilic stains is less thanabout 40; alternatively, less than about 35. The total ΔE measured forthe resistance of the coating composition (test samples F-I) to thehydrophobic stains is less than about 45; alternatively, less than about35. In comparison, the total ΔE values measured for the removal of thesame stains on comparative paint samples A-E are observed to be usuallyhigher than the values measured for test paint samples F-I. The lower ΔEvalues are obtainable without sacrificing scrub resistance asdemonstrated by the similarity in the number of scrub cycles measuredfor the test samples F-I and the control sample, as well as comparativesamples A-E. Finally, the roller stability of the test samples F-Ipassed 4 cycles, while the comparative samples A-E failed after only 1or 2 cycles. Thus the test samples F-I exhibit improved roll stabilityas compared to the comparative samples A-E.

TABLE 5 Summary of the Total Stain Removal (ΔE), Roll Stability, andScrub Resistance Measured For Paint Samples A-I Paint Sample A B C D E FG H I Emulsion Sample 1 2 3 4 5 6 7 8 9 b/c (PAM/MAA) 0 0.66 0.66 0.660.66 0.66 0.66 0.66 0.66 Total ΔE (Hydrophilic and 89.85 88.93 84.1880.30 81.42 56.91 68.38 59.19 68.36 Hydrophobic stains) Scrub cycles(vs. control at 789) 920 1129 1156 1015 712 941 892 782 766 RollerStability 1 2 1 2 1 4 4 4 4

Within this specification embodiments have been described in a way whichenables a clear and concise specification to be written, but it isintended and will be appreciated that embodiments may be variouslycombined or separated without parting from the invention. For example,it will be appreciated that all preferred features described herein areapplicable to all aspects of the invention described herein.

The foregoing description of various forms of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formsdisclosed. Numerous modifications or variations are possible in light ofthe above teachings. The forms discussed were chosen and described toprovide the best illustration of the principles of the invention and itspractical application to thereby enable one of ordinary skill in the artto utilize the invention in various forms and with various modificationsas are suited to the particular use contemplated. All such modificationsand variations are within the scope of the invention as determined bythe appended claims when interpreted in accordance with the breadth towhich they are fairly, legally, and equitably entitled.

1. An emulsion polymer composition comprising, as polymerized units: a)at least one nonionic or anionic unsaturated monomer in an amountranging between about 78 wt. % to less than 100 wt. % based on theoverall weight of the polymer composition b) one or more strong acidmonomer in an amount ranging from about 0.01 wt. % to 2 wt. % based onthe overall weight of the polymer composition; and c) at least one loweralkyl acrylate monomer in an amount ranging between about 1 wt. % to 20wt. % based on the overall weight of the polymer composition.
 2. Theemulsion polymer according to claim 1, wherein the polymerized units areformed at a pH between 3 and
 9. 3. The emulsion polymer according toclaim 1, wherein the ethylenically unsaturated nonionic or anionicmonomer is methacrylic acid, butyl acrylate, methyl methacrylate, butylmethacrylate, styrene.
 4. The emulsion polymer according to claim 1,wherein the strong acid monomer is ethyl methacrylate phosphate,phosphate esters of polypropylene glycol monomethacrylate, or a mixturethereof.
 5. The emulsion polymer according to claim 1, wherein the loweralkyl acrylate monomer is methyl acrylate, ethyl acrylate, propylacrylate, or a mixture thereof.
 6. A coating composition comprising anemulsion polymer dispersed in an aqueous medium, the emulsion polymercomprising, as polymerized units: a) at least one nonionic or anionicunsaturated monomer in an amount ranging between about 78 wt. % to lessthan 100 wt. % based on the overall weight of the polymer composition b)one or more strong acid monomer in an amount ranging from about 0.01 wt.% to 2 wt. % based on the overall weight of the polymer composition; andc) at least one lower alkyl acrylate monomer in an amount rangingbetween about 1 to 20 wt. % based on the overall weight of the polymercomposition; wherein the polymerized units are formed at a pH between 3and
 9. 7. The coating composition according to claim 6, wherein thecoating composition comprises less than about 50 grams per liter of avolatile organic compound (VOC).
 8. The coating composition according toclaim 6, wherein the ethylenically unsaturated nonionic or anionicmonomer is methacrylic acid, butyl acrylate, methyl methacrylate, butylmethacrylate, styrene.
 9. The coating composition according to claim 6,wherein the strong acid monomer is ethylmethacrylate phosphate,phosphate esters of polyethylene glycol mono(meth)acrylate, phosphateesters of polypropylene glycol mono(meth)acrylate, or a mixture thereof.10. The coating composition according to claim 6, wherein the loweralkyl acrylate monomer is methyl acrylate, ethyl acrylate, propylacrylate, or a mixture thereof.
 11. The coating composition according toclaim 6, wherein the coating composition further comprises an organicpigment, and inorganic pigment, or a mixture thereof.
 12. The coatingcomposition according to claim 6, wherein the coating compositionfurther comprises one or more additives selected from the group ofsurfactants, dispersants, extenders, rheology modifiers, defoamers,coalescent agents, and opacifiers.
 13. The coating composition accordingto claim 6, wherein the emulsion polymer is present in an amount rangingfrom about 5 to 70 wt. % based on the entire weight of the coatingcomposition.
 14. The coating composition according to claim 13, whereinthe emulsion polymer is present in an amount ranging from about 10 to 60wt. % based on the entire weight of the coating composition.
 15. Amethod of using the coating composition of claim 6, wherein the coatingcomposition is applied to a surface of a substrate to form a film orcoating layer on the surface; wherein the film or coating layer isresistant to both hydrophilic stains and hydrophobic stains.
 16. Themethod according to claim 15, wherein a total ΔE measured for theresistance of the film or coating layer to both the hydrophilic stainsand hydrophobic stains is less than about 80; wherein the hydrophilicstains include mustard, ketchup, wine, coffee, and fountain ink; whereinthe hydrophobic stains include ballpoint pen, No. 2 pencil, blue crayon,grease pencil, lipstick #1 (CoverGirl Hot Passion), lipstick #2(Maybelline Royal Red), and a consumers union stain.
 17. The methodaccording to claim 16, wherein the total ΔE measured for the resistanceof the film or coating layer to both the hydrophilic and hydrophobicstains is less than about
 75. 18. The method according to claim 16,wherein the total ΔE measured for the resistance of the film or coatinglayer to hydrophilic stains is less than about
 40. 19. The methodaccording to claim 16, wherein the total ΔE measured for the resistanceof the film or coating layer to hydrophobic stains is less than about35.
 20. The method according to claim 15, wherein the roller stabilityof the coating is at least four cycles.